This invention relates to system and method for charged particle beam. More specifically, embodiments of the present invention provides a apparatus for generating and focusing primary charged particle beam onto a conductive or non-conductive specimen and collecting the released charged particles and/or X-ray from the specimen to form an image/or a spectrum of the specimen. Merely by way of example, the present invention has been used to provide a low-landing scanning electron microscope, but it would be recognized that the invention has a much broader range of applicability.
The low landing energy and high resolution charged particle beam apparatus, (e.g. scanning electron microscope, or SEM) is an important metrology tool for inspection, review of defects of semiconductor wafer and for measurement of the critical dimensions (CD) of the integrated circuit (IC) pattern. It can help accelerate the new wafer processing technology ramp and improve the yield during mass production. Over the past, various conventional SEM systems and related techniques have been developed for different purpose. However, it still is a big challenge for high resolution, low landing energy and small spot size for prior arts.